Once invoked, the default prolog looks in your home directory for a
file named prolog.ini, and if it finds one, loads it. Stand-alone
programs also look for and load prolog.ini. Runtime systems do not.
Typically, prolog.ini files are used to define file search paths,
library directories, and term expansions.
If the +f option is specified, the initialization file prolog.ini is not
loaded.